This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. There is significant interest in the development of novel non-invasive techniques for the early diagnosis of Alzheimer disease (AD). The increasing demand for a noninvasive measurement has driven the development of imaging based methods. Magnetic resonance imaging (MRI) is non-invasive and routinely performed in the setting of neurological disease, implementation of new MRI-based techniques for the diagnosis and prognosis of AD is especially advantageous. An alternate MR contrast mechanism is T1[unreadable], the spin lattice relaxation time constant in the rotating frame, which generates a different type of contrast than that seen with conventional relaxation times (T1 and T2). T1[unreadable] relaxation phenomena in biological tissues have been extensively studied and shown to be sensitive to physio-chemical processes (e.g. spin-spin interaction, chemical exchange). In proteins and biological tissues, exchange between protons in different environments contributes to T1[unreadable] relaxation. T1[unreadable] MRI has been widely used to characterize breast cancer tissue, monitor the level of cartilage degeneration and delineate brain tumors. The current study deal with the measurement of T1[unreadable] in the brain of AD, MCI and age matched control, and determine the role of T1[unreadable] in discrimination of these three cohorts.